1. Field of the Invention
This invention pertains to telecommunications components for use in telecommunications systems such as cable television networks.
2. Description of the Prior Art
In the telecommunications industry and more particularly in the video transmission industry (e.g., the cable television environment), broad-band radio frequency (RF) signals (i.e., 5 MHz to 1 GHz) are carried over coax conductors from a headend to consumers. At the headend of the system, numerous signals are manipulated to achieve a wide variety of functions and objectives. For example, signals carried on numerous coax cables may be combined onto a single coax conductor. Similarly, a signal on a main coax conductor may be divided into a plurality of signals carried on branch coax conductors. Additionally, signals may be added or removed from a main conductor through directional couplers or the like.
In addition to combining, splitting, diverting or adding signals, the headend will also include apparatus for modifying signals. For example, in order to adequately tune the system, it may be desirable to provide attenuators or the like to attenuate a signal to a desired level. Further, as a broadband RF signal is carried over a length of cable, the high frequency range of the signal may be attenuated more than a low frequency range of the signal. As a result, equalizers are utilized to modify the signal to have a level intensity throughout its frequency range.
Frequently, tuning is accomplished through the use of plug-in devices (e.g., attenuators or equalizers). Exemplary systems including plug-in devices are disclosed in U.S. Pat. No. 5,955,930, which is hereby incorporated by reference.
Currently the cable television environment uses plug-in devices that break the signal paths while changing out the plug-in devices. However, with the new opportunities that are present in the cable television environment (e.g., telephony, data and 911 service), it is important to prevent signal paths from being broken. Thus, what are needed are plug-in devices for the cable television industry that prevent signal paths from being broken when plug-in devices are changed out.